JP5114997B2 - Tire testing apparatus and tire testing method - Google Patents

Description

  The present invention relates to a tire testing apparatus and a tire testing method, and more particularly to a tire testing apparatus and a tire testing method capable of evaluating the adhesion of a tread splice portion.

  The tire is evaluated by an actual vehicle running test or a tire test. As a tire evaluation method, for example, there is a method of evaluating the adhesiveness of a tread splice portion. The method for evaluating the adhesiveness of the tread splice portion is to evaluate the measurement target tire based on the peeling that occurs in the joint portion (tread splice portion) of the constituent members constituting the tread portion. In the actual vehicle running test, road running is performed by a vehicle equipped with a measurement target tire. A conventional method for evaluating the adhesiveness of the tread splice has been performed by an actual vehicle running test. When running with the tread splice part peeled off, the measurement target tire may burst (burst). In the actual vehicle running test, it is possible to detect the peeling of the tread splice part by the driving feeling of the driver. Therefore, in the actual vehicle running test, since the test can be completed before bursting, the adhesion of the tread splice part can be evaluated by peeling off the tread part. However, the evaluation of the adhesion of the tread splice part by the actual vehicle running test is greatly affected by the running conditions and the road surface, so that the reproducibility is poor and high accuracy cannot be obtained.

  On the other hand, the conventional tire test has the advantage that it can be tested indoors and is not easily affected by the running conditions and the road surface. On the other hand, the tire is evaluated by a destructive test in which the test is performed based on a burst. The conventional tire testing apparatus and the tire testing method according to Patent Document 1 are, for example, a drum-type tire testing machine, which is deteriorated by heat by cooling with contact with a relatively low temperature outside air or ventilation. Is to test the durability of the measurement target tire against fatigue of the structure due to an external load such as strain.

JP-A-7-151645

However, in the conventional tire testing apparatus and tire testing method according to Patent Document 1, even if the heat generation itself is suppressed, the measurement target tire bursts due to an external load such as strain. For this reason, it was not possible to evaluate adhesiveness based on peeling of the tread splice before bursting.

  The present invention has been made in view of the above, and relates to a tire testing apparatus and a tire testing method capable of accurately evaluating the adhesiveness of a tread splice before bursting.

In order to solve the above-described problems and achieve the object, a tire test apparatus according to the present invention is a tire test in which a measurement target tire is rotated with respect to a temporary road surface in a state where a driving force or a braking force is continuously applied. A surface temperature measuring means for measuring the surface temperature of the tread portion of the rotating measurement target tire, and the surface temperature distribution of the tread portion currently acquired is lower than the surface temperature distribution of the tread portion acquired immediately before And a temperature change detecting means for detecting the temperature change of the surface temperature of the tread portion, and determining that the splice portion of the tread portion has peeled off by detecting the temperature change. characterized in that it.

  Further, in the present invention, in the tire test apparatus, the temperature change detecting means detects a local temperature change of the measured surface temperature.

Further, according to the present invention, in the tire test method described above, a procedure for rotating the measurement target tire with respect to the temporary road surface in a state where the driving force or the braking force is continuously applied by the tire testing machine, and the tread of the rotating tire The surface temperature distribution of the tread portion when there is a temperature lower than the surface temperature distribution of the tread portion acquired immediately before It includes a procedure for detecting the temperature change as a temperature change and a procedure for determining that the splice portion of the tread portion has been peeled off by detecting the temperature change.

  In the present invention, in the tire test method, the procedure for detecting the temperature change of the measured surface temperature is to detect a local temperature change of the measured surface temperature.

  According to the present invention, when the tire to be tested is rotated in a state where the driving force or the braking force is continuously applied by the tire testing machine, the measurement of the surface temperature of the tread portion and the temperature of the measured surface temperature are performed. A change, ie a local temperature change of the measured surface temperature, is detected. Here, when the tread splice part peels off, the surface temperature of the tread part locally changes. Therefore, by detecting the temperature change of the measured surface temperature by the temperature change detecting means, it is possible to detect the separation of the tread splice portion. In other words, even with the tire testing machine, it is possible to detect the occurrence of separation of the tread splice part at the stage before the measurement target tire bursts. Thereby, evaluation of a tread splice part can be performed with high accuracy.

  According to the present invention, in the tire testing apparatus, the tire testing machine stops the rotation of the measurement target tire when the temperature change is detected by the temperature change detecting means.

  In the tire testing method according to the present invention, the tire testing method further includes a step of stopping rotation of the measurement target tire by the tire testing machine when a temperature change is detected.

  According to the present invention, the temperature change detecting means detects the temperature change of the surface temperature of the tread part, for example, the local temperature change of the measured surface temperature, so that the tread splice part is peeled off, that is, the tread part is The operation of the tire testing machine can be stopped in a locally peeled state. Therefore, it is possible to visually recognize the peeling state of the tread splice before the measurement target tire bursts. Thereby, the adhesiveness of a tread splice part can be evaluated with high accuracy.

  Moreover, in this invention, in the said tire test apparatus, a tire test machine has a slip ratio control means which controls the slip ratio with respect to the temporary road surface of a measurement object tire, and a slip ratio is the range of 10%-30%. It is characterized by that.

According to the present invention, by controlling the slip ratio by the slip ratio control means, it is possible to apply a stable braking force or driving force as compared with the actual vehicle running test. Therefore, the adhesiveness of the tread splice can be evaluated with high accuracy. Moreover, the test which peels an efficient and stable tread splice part can be performed by setting a slip ratio in the range of 10%-30%.

  According to the present invention, in the tire testing apparatus, the tire testing machine increases the slip ratio stepwise.

  In the present invention, the tire test method further includes a step of gradually increasing the slip ratio of the measurement target tire with respect to the temporary road surface.

  According to the present invention, it is possible to increase the slip rate in a stepwise manner with respect to the measurement target tire up to a limit value at which the tread splice part peels off. Thereby, since the tires to be measured can be compared based on the set limit value of the slip ratio, the adhesiveness of the tread splice portion can be evaluated with high accuracy.

  In the present invention, in the tire testing apparatus, the tire testing machine further includes a load adding unit that applies a load to the measurement target tire with respect to the temporary road surface, and the load addition unit measures the load of the measurement target tire. The maximum allowable load of the target tire is controlled to 30% or less and more than 0%.

  According to the present invention, the measurement target tire is caused by factors other than separation of the tread splice, such as the rotation of the tire becoming unstable by performing a test in a load range of 30% or less from the maximum allowable load of the measurement target tire. By suppressing the damage, it is possible to perform an evaluation test limited to peeling of the tread splice part.

  According to the present invention, in the tire testing apparatus, the tire testing machine further includes a test elapsed time counter, and the test elapsed time counter measures the test elapsed time from the start of the test until the temperature change is detected. Features.

  According to the present invention, in the tire test method, the tire testing machine further includes a procedure for measuring a test elapsed time from the start of the test until a temperature change is detected.

  According to the present invention, the test elapsed time counter starts counting from the start of the test, and when the temperature change is detected, that is, when it is determined that peeling has occurred in the tread splice, the count of the test time that has been counted is performed. The measurement target tire can be compared based on the length of the counted test time. Thereby, the adhesiveness of a tread splice part can be evaluated with high accuracy.

  The tire testing apparatus and the tire testing method according to the present invention have an effect that the adhesiveness of the tread splice can be evaluated with high accuracy.

  Hereinafter, a tire testing apparatus and a testing method according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[Embodiment]
Drawing 1 is a figure showing the example of composition of the tire testing device concerning an embodiment. FIG. 2 is an enlarged view of a test target tire of the tire testing apparatus according to the embodiment. FIG. 3 is an enlarged view of a test target tire of the tire test apparatus according to the embodiment. As shown in FIG. 1, a tire testing apparatus 1 according to an embodiment includes a tire testing machine 2, a measurement target tire 3, a surface temperature measuring device 4, a control device 5, and an input / output device 6. ing. The tire testing machine 2 shown in the embodiment describes the drum type tire testing machine 2 that rotates the measurement target tire 3 by at least one rotating drum, but the present invention is limited to this. It is not a thing. Examples of other tire testing machines include a belt type tire testing machine. A belt-type tire testing machine rotates a measurement target tire by bringing it into contact with an endless belt wound between two rollers rotated by driving means.

  The tire testing machine 2 is a tire rotating unit that rotates the measurement target tire 3 with respect to the temporary road surface. The tire testing machine 2 is also a slip ratio control means for controlling the slip ratio by controlling the braking force or the driving force. Furthermore, the tire testing machine 2 is also a load adding unit that applies a load by bringing the measurement target tire 3 into contact with the temporarily mounted road surface. The tire testing machine 2 includes a tire shaft 21, a tire support rotating device 22, a tire load adding device 23, a drum 24, a drum rotating shaft 25, and a drum rotational force applying device 26.

  The tire shaft 21 rotatably supports the measurement target tire 3. One end of the tire shaft 21 in the axial direction can be fixed to a rim (not shown), and the other end is connected to or integrally formed with the tire support rotation device 22. Thus, the rotational force, braking force, and driving force activated by the tire support rotating device 22 can be transmitted to the measurement target tire 3 via the tire shaft 21 in response to the signal output by the control device 5. When the measurement target tire 3 is fixed to the tire shaft 21, the measurement target tire 3 is assembled on the rim, and a tire assembly (not shown) is fixed to the tire shaft 21.

  The tire support rotating device 22 supports the measurement target tire 3 so as to be rotatable around the tire shaft 21. The tire support rotation device 22 can move the measurement target tire 3 fixed to the tire shaft 21 in the vertical direction, that is, the load direction (arrow A direction) and the yaw direction, that is, the tire slip direction (arrow B direction). To support. The tire support rotation device 22 is a tire rotation force applying device (for example, a motor generator) (not shown) that applies a tire rotation force around the tire shaft 21, that is, in the tire rotation direction (arrow C direction in the figure) to the measurement target tire 3. A tire slip direction moving device (not shown) that moves the tire 3 in the tire slip direction (yaw direction) is provided. These devices are connected to the control device 5, and are given to the measurement target tire 3 by a tire torque control signal and a tire slip angle control signal output from a tire testing machine control unit 55 described later of the control device 5. The rotational force and the slip angle of the measurement target tire 3 are adjusted. The tire support rotation device 22 outputs the rotation speed of the tire shaft 21 to the control device 5. Thereby, the control device 5 can calculate the rotation speed of the measurement target tire 3 fixed to the tire shaft 21.

  The tire load adding device 23 is an additional load unit, and applies a load to the measurement target tire 3 by bringing the measurement target tire 3 into contact with the drum 24 that is a temporarily mounted road surface. The tire load adding device 23 moves the tire shaft 21 that is rotatably supported by the tire support rotating device 22 in the load direction (vertical direction), and moves the tire shaft 21 in the load direction to perform measurement. The target tire 3 is moved in the load direction, and the distance of the measurement target tire 3 with respect to the drum 24 is changed. That is, the tire load adding device 23 changes the load applied to the measurement target tire 3 by changing the distance of the measurement target tire 3 with respect to the drum 24. The tire load adding device 23 is connected to the control device 5 and controls the load applied to the measurement target tire 3 by a load control signal output from the load adding unit 54 of the control device 5.

  The drum 24 is a temporary road surface with which the measurement target tire 3 comes into contact in the drum-type tire test 2. The drum 24 rotates the contacted measurement target tire 3 in the tire rotation direction. The measurement target tire 3 rotates in a direction opposite to the direction in which the drum 24 rotates (for example, counterclockwise in FIG. 3) with respect to the direction in which the drum 24 rotates (for example, clockwise in FIG. 3). In the embodiment, the drum 24 is set in the vertical direction with respect to the measurement target tire 3, but the present invention is not limited to this.

  The drum rotation shaft 25 supports the drum 24 rotatably. One end of the drum rotation shaft 25 in the axial direction is fixed to the drum 24, and the other end is connected to or integrally formed with the drum rotation force applying device 26. Thereby, the tire rotational force by the drum rotational force applying device 26 can be transmitted to the drum 24 via the drum rotational shaft 25.

  The drum rotation force applying device 26 is, for example, a motor generator, and applies a drum rotation force around the drum rotation shaft 25, that is, in the drum rotation direction (direction of arrow D in the figure) to the drum 24. The drum rotational force applying device 26 is connected to the control device 5, and adjusts the drum rotational force applied to the drum 24 by a drum rotational force control signal output from the tire testing machine control unit 55 of the control device 5. It is. In addition, the drum rotational force applying device 26 outputs the rotational speed of the drum rotation shaft 25 to the control device 5. Thereby, the control apparatus 5 can calculate the rotational speed of the drum 24 at the time of a tire test.

  The tire 3 to be measured is assembled to a wheel (not shown) and fixed to the tire shaft 21 by fixing the wheel to the tire shaft 21. The measurement target tire 3 basically rotates by the drum rotational force applied to the drum 24 by contacting the drum 24 of the tire testing machine 2. The measurement target tire 3 includes a tread portion 3a, a sidewall portion (not shown), and a tire bead portion. As shown in FIG. 2, the tread portion 3 a includes a carcass layer 31, a belt layer 32, and a tread rubber 33.

  The carcass layer 31 constitutes a so-called skeleton of the measurement target tire 3. The carcass layer 31 is composed of a single strip-shaped member in which a cord such as organic fiber or steel is covered with rubber. The measurement target tire 3 is formed in an annular shape by connecting both ends of the carcass layer 31 in the tire circumferential direction.

  The belt layer 32 is configured by, for example, laminating a single belt-shaped member in which a cord such as an organic fiber is covered with rubber while being stacked. The belt layer 32 is laminated in the tire radial direction outer periphery of the carcass layer 31 in the circumferential direction. As a result, the belt layer 32 tightens the carcass layer 31 and reinforces and maintains the shape of the outer periphery in the tire radial direction including the overlapping portion of the carcass layer 31.

  The tread rubber 33 is a portion that comes into contact with the road surface, and is made of undertread rubber, side tread rubber, cap tread rubber, or the like. A portion of the tread rubber 33 that comes into contact with the road surface (including the temporary road surface) has a tread pattern formed by a land portion and a groove portion. The tread rubber 33 is formed with an overlapping surface that is continuous in the tire width direction, that is, a tread splice portion 3b at the time of molding. Note that, in the measurement target tire 3, a portion other than the tread portion 3 a, that is, the carcass layer 31 in the sidewall portion and the tire bead portion also has an overlapping surface that is continuous in the tire width direction.

  In the embodiment, the tread splice portion 3b is an overlapping surface formed continuously in the tire width direction of the tread rubber 33 in the tread portion 3a. In the tread splice portion 3b, for example, separation occurs when a sudden change such as braking force or driving force is applied from the outside. More specifically, when a sudden change such as braking force or driving force is applied from the outside, as shown in FIG. The tire rotation direction of the target tire 3) acts on the tread portion 3a. Therefore, since the tensile force F acts on the tread splice portion 3b, a shearing force is generated in the tread splice portion 3b in the tire circumferential direction. As shown in FIG. 3, in the tread splice portion 3b, one end portion 33a and the other end portion 33b of the tread rubber 33 are peeled off by a shearing force. When the tread splice portion 3b is peeled off, a gap K is generated between the one end portion 33a and the other end portion 33b. Note that when the measurement target tire 3 continues to rotate with the tread splice 3b peeled off, the generated gap K expands and the tread 3a is missing. And when the omission of the tread portion 3a proceeds, the measurement target tire 3 may eventually burst (burst).

  The surface temperature measuring device 4 is surface temperature measuring means for measuring the surface temperature of the tread portion 3a of the rotating measurement target tire 3. The surface temperature measuring device 4 is a device having a temperature resolution as represented by infrared thermography, for example. The surface temperature measuring device 4 is a device that can also measure an object that moves at high speed and an instantaneous change in surface temperature, and can be fixed to a place at a certain distance from the measuring point by, for example, a tripod.

  The surface temperature measuring device 4 measures the surface temperature by measuring the temperature at a sampling point at a plurality of locations in the tire width direction of the tread portion 3a at a time. The surface temperature measuring device 4 is connected to the control device 5 and outputs the temperature at each sampling point to the control device 5 for each sampling. Thereby, the control apparatus 5 detects the temperature change which generate | occur | produced locally in the tread part 3a based on the temperature in each sampling point for every sampling.

  Here, the predetermined unit time is a time interval during which the surface temperature measuring device 4 can measure the surface temperature at a plurality of locations of the tread portion 3a while the measurement target tire 3 rotates once. Alternatively, the predetermined unit time is a time interval that allows the entire circumference of the surface of the tread portion 3a to be measured per predetermined number of revolutions according to the speed of the measurement target tire 3.

  The control device 5 controls the tire testing device 1. The control device 5 includes at least an input / output port (I / O) 51, a storage unit 52, and a processing unit 53. The input / output port (I / O) 51, the storage unit 52, and the processing unit 53 are connected to each other, for example, and can exchange data with each other. An input / output device 6 is connected to the control device 5.

  The storage unit 52 stores a tire test method program in which the tire test method according to the embodiment is incorporated. Here, the memory | storage part 52 can be comprised by storage means, such as memory like RAM (Random Access Memory). The storage unit 52 may be provided in the processing unit 53. The storage unit 52 appropriately stores, for example, temperature distribution data of the tread rubber 33 before the temperature change, test time data counted by the test elapsed time counter unit 58, and the like. Further, the tire test method program is not necessarily limited to a single configuration, and cooperates with a program already stored in a computer system, for example, a separate program represented by an OS (Operating System). The function may be achieved. The “computer system” here includes an OS and hardware such as peripheral devices. Note that the storage unit 52 classifies the measurement location for each map and stores the position where the temperature change has occurred for each classification, for example, so that the temperature change position map data for grasping the temperature change position for each test. Etc. may be stored.

  The processing unit 53 includes a memory such as a RAM and a ROM, and a CPU (Central Processing Unit). The processing unit 53 includes at least a load adding unit 54, a tire testing machine control unit 55, a slip ratio control unit 56, a temperature change detection unit 57, and a test elapsed time counter unit 58.

  The load addition unit 54 is a load addition unit that applies a load to the measurement target tire 3 with respect to the drum 24. The load adding unit 54 outputs a load control signal to the tire load adding device 23 based on the set load input from the input / output device 6. Accordingly, the tire load adding device 23 changes the distance of the measurement target tire 3 with respect to the drum 24 via the tire shaft 21 and applies a set load to the measurement target tire 3. Therefore, the tire testing machine 2 can perform a test in which a set load is applied to the measurement target tire 3 with respect to the drum 24.

  The load on the measurement target tire 3 is preferably set to a maximum allowable load of 30% or less. When a test is performed with a maximum allowable load exceeding 30% applied to the measurement target tire 3, a failure of the measurement target tire 3 due to factors other than separation of the tread splice portion 3b such as fatigue due to an external load is likely to occur. Become. This makes it impossible to perform an evaluation test limited to peeling of the tread splice 3b. Accordingly, by setting the load on the measurement target tire 3 to 30% or less, the separation of the measurement target tire 3 due to factors other than the separation of the tread splice portion 3b is suppressed. Thereby, the evaluation test limited to peeling of the tread splice portion 3b can be performed. The maximum allowable load is “maximum load capacity” defined by JATMA, a maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “LOAD CAPACITY” defined by ETRTO.

  The tire testing machine control unit 55 controls the operation of the tire testing machine 2. The tire testing machine control unit 55 outputs output signals to various devices of the tire testing machine 2. Examples of the output signal include a tire torque control signal and a drum torque control signal. Examples of the various devices include a tire support rotation device 22 and a drum rotation force application device 26.

  When the set travel speed is input from the input / output device 6, the tire testing machine control unit 55 rotates the tire rotation force applying device 22 to rotate the tire 3 to be measured at the travel speed based on the set travel speed. A drum rotational force output signal is output to the force output signal or the drum rotational force applying device 26 to control the drum rotational force or the tire rotational force. The tire testing machine control unit 55 performs feedback control based on the traveling speed of the measurement target tire 3.

  The slip ratio control unit 56 is slip ratio control means for controlling the slip ratio for the measurement target tire 3. The slip ratio control unit 56 calculates the rotation speed of the drum 24 based on the set slip ratio input from the input / output device 6 and the set travel speed output from the tire support rotation device 22. The slip ratio control unit 56 uses the rotation speed calculated based on the set slip ratio and the set travel speed when the measurement target tire 3 rotated by the tire testing machine 2 is rotated by the input / output device 6 at the set slip ratio. Output to the testing machine controller 55. When the tire testing machine control unit 55 rotates the measurement target tire 3 at the set slip ratio, the tire testing machine control unit 55 rotates the drum 24 at a rotation speed based on the rotation speed from the slip ratio control unit 56, and based on the set travel speed. In order to rotate the measurement target tire 3 at the traveling speed, the tire rotational force output device 22 outputs the tire rotational force output signal or the drum rotational force output device 26 outputs the drum rotational force output signal to the drum rotational force or tire. Control the rotational force. Note that the tire testing machine control unit 55 can perform feedback control based on the traveling speed of the measurement target tire 3 and the rotational speed of the drum 24.

  Here, the slip ratio is a numerical value expressed as a percentage obtained by dividing the difference between the rotational speed of the drum 24 and the traveling speed of the measurement target tire 3 by the rotational speed of the drum 24. Here, assuming that the rotational speed of the drum 24 is Vd and the traveling speed of the measurement target tire 3 is Vt, the slip ratio (S) is represented by S = (Vt−Vd) / Vd × 100. Here, when the numerical value of the slip ratio is positive, the vehicle body is accelerated in the actual vehicle running test. That is, when the numerical value of the slip ratio is positive, the rotational speed (Vd) of the drum 24 is lower than the traveling speed (Vt) of the measurement target tire 3, and the measurement target tire 3 is in a driving state. On the other hand, when the slip ratio is negative, the vehicle body is decelerated in the actual vehicle running test. That is, when the slip ratio is negative, the rotational speed (Vd) of the drum 24 is higher than the running speed (Vt) of the measurement target tire 3, and the measurement target tire 3 enters a braking state.

  The slip ratio is preferably controlled in the range of 10% to 30%. When the slip ratio is less than 10%, the tread splice portion 3b cannot be efficiently peeled off. Further, if the slip ratio exceeds 30%, the rotation of the measurement target tire 3 becomes unstable, so that it is difficult to stably generate the separation of the tread splice portion 3b. Therefore, by controlling the slip ratio in the range of 10% to 30%, it is possible to perform a test for causing the tread splice portion 3b to peel stably and efficiently.

  The slip ratio control unit 56 can also increase the slip ratio stepwise. Thereby, about the measurement object tire 3, the adhesiveness of the tread splice part 3b of the measurement target tire 3 can be accurately evaluated up to the limit value at which the tread splice part 3b peels off. Moreover, the slip ratio control part 56 can test in a shorter time compared with the tire test which makes a slip ratio constant by increasing a slip ratio in steps.

  The temperature change detection unit 57 is a temperature change detection unit that acquires the surface temperature distribution of the tread portion 3a measured by the surface temperature measuring device 4 and detects the temperature change between the measured surface temperature distributions of the tread portion 3a. . The temperature change detection unit 57 detects the temperature of the surface temperature of the tread portion 3a when there is a portion of the surface temperature distribution of the tread portion 3a that is currently acquired that has a temperature lower than the surface temperature distribution of the tread portion 3a acquired immediately before. It is detected as a change, and it is determined that the tread splice portion 3b is peeled off. In the embodiment, it is determined that peeling has occurred in the tread splice portion 3b when a temperature change larger in the minus direction than a predetermined temperature difference (for example, −10 ° C.) input in advance is detected before the test.

  Here, the mechanism by which the surface temperature of the tread portion 3a changes due to the peeling of the tread splice portion 3b will be described. When the measurement target tire 3 rotates, a frictional force is generated by the tread portion 3 a coming into contact with the drum 24. Due to this frictional force, heat is generated on the surface of the tread portion 3a constituted by the tread rubber 33, and the temperature of the tread rubber 33 rises by storing heat. When the tread splice portion 3 b is peeled off, a gap K is generated in a part of the tread rubber 33.

  When the gap K is generated, the rubber inside the tread rubber 33 is exposed to the outside. The temperature of the rubber inside the exposed tread rubber 33 is lower than the temperature of the rubber forming the surface of the tread portion 3a that generates heat due to frictional force. In other words, the surface temperature of the tread portion 3a is lowered when the tread splice portion 3b is peeled and the portion peeled is lower than the other portions that are not peeled. Therefore, the surface temperature of the tread portion 3a changes locally as the tread splice portion 3b peels off.

  In other words, the tread portion 3a of the measurement target tire 3 rotated by the tire testing machine 2 has a gap K when the tread splice portion 3b is peeled off. Therefore, the tread splice portion 3b is not peeled off. In comparison, the surface temperature is lowered. Therefore, the surface temperature of the tread portion 3a of the measurement target tire 3 rotating by the tire testing machine 2 is measured by the surface temperature measuring device 4, and the temperature change is detected by the temperature change detecting portion 57, whereby the tread splice portion. 3b peeling can be detected. As a result, the tire testing machine 2 can also detect the separation of the tread splice portion 3b before the measurement target tire 3 bursts, which was possible only in the actual vehicle running test.

  Here, the tire testing machine control unit 55 can stop the rotation of the measurement target tire 3 when the temperature change detection unit 57 detects the temperature change of the surface temperature of the tread portion 3a. That is, the control device 5 can issue an operation stop command to the tire support rotation device 22 and the drum rotation force application device 26.

  The test elapsed time counter unit 58 counts the test elapsed time from the start of the test. The test elapsed time counter unit 58 measures the test elapsed time from the start of the test until the temperature change is detected by the temperature change detection unit 57. That is, the test elapsed time counter unit 58 starts counting the test time at the start of the test of the tire testing machine 2, and counts based on the count stop command output when the temperature change detection unit 57 detects the temperature change. Stop counting the test time. Thereby, based on the length of the test time counted by the test elapsed time counter unit 58, the measurement target tire 3 is compared, such as a comparison with a reference test time or a comparison between various measurement target tires 3. Therefore, the adhesiveness of the tread splice portion 3b can be evaluated with high accuracy. It can be evaluated that the measurement target tire 3 having a longer test time has better adhesion of the tread splice portion 3b.

  The input / output device 6 includes an input device 61 and an output device 62. The input device 61 sends other data such as the set traveling speed, the set load, the specified temperature difference, the set slip rate, the initial slip rate increase time, the slip rate increase time, and the slip rate increase amount of the measurement target tire 3 to the control device 5. Input. The control device 5 generates a tire torque control signal, a load control signal, a slip angle control signal, a drum torque control signal, and the like based on data based on the test conditions input by the input device 61 and other data. The rotation direction of the measurement target tire 3 and the drum rotation force are controlled. As the input device 61, an input device such as a keyboard, a mouse, and a microphone can be used.

  The output device 62 includes a surface temperature distribution of the tread portion 3a during the test, a change with time in the surface temperature of the tread portion 3a, a load during the test, a running speed of the measurement target tire 3, a rotation speed of the drum 24, a slip ratio, and the like. The data is displayed. As the input device 61, a CRT (Cathode Ray Tube), a liquid crystal display device, or the like can be used. These data may be output to a print (not shown). Here, the input / output device 6 may be provided in a terminal device (not shown) and may be configured to be able to access the control device 5 via a portable terminal by either a wired or wireless method.

  Next, a tire test method according to the embodiment will be described. FIG. 4 is a diagram illustrating a flow of the tire test method according to the embodiment.

  First, the measurer uses the input / output device 6 to set the running speed (V), the set load (G), the specified temperature difference (−ΔT), and the set slip rate (S ), Initial slip rate increase time (tx), slip rate increase time (Δtx), slip rate increase amount (ΔS), and the like are input (step ST1).

  Next, the tire testing machine 2 applies a set load (G) to the measurement target tire 3 (step ST2). Here, the load application unit 54 outputs a load control signal to the tire load application device 23 so that the set load (G) is applied to the measurement target tire 3. The tire load adding device 23 is set to the measurement target tire 3 by moving the measurement target tire 3 in the load direction in accordance with a load control signal from the load addition unit 54 and changing the distance of the measurement target tire 3 with respect to the drum 24. A load (G) is added. In the embodiment, the load of the measurement target tire 3 during the tire test is constant at the set load (G), but the present invention is not limited to this. For example, the test elapsed time during the test It may be increased step by step.

  Next, the tire testing machine 2 rotates the measurement target tire 3 at a set speed (V) (step ST3). Here, the tire testing machine control unit 55 controls the tire support / rotation device 22 to rotate the measurement target tire 3 at the set traveling speed (V), or the drum rotation force applying device 26 to control the drum rotation. Output at least one of the signals. In the embodiment, the tire testing machine control unit 55 outputs a drum rotation control signal to the drum rotation force applying device 26 so as to rotate the measurement target tire 3 at the set travel speed (V). The drum rotational force imparting device 26 rotates the measurement target tire 3 at the set traveling speed (V) by controlling the drum rotational force based on the drum rotational control signal from the tire testing machine control unit 55.

  Next, the tire testing machine 2 rotates the measurement target tire 3 at the set slip ratio (S) (step ST4). Here, the slip ratio control unit 56 outputs the calculated rotation speed to the tire testing machine control unit 55 so that the measurement target tire 3 is rotated at the slip ratio (S). Here, the tire testing machine control unit 55 controls the tire support rotating device 22 to rotate the tire so that the drum 24 rotates at the set traveling speed (V) and the measurement target tire 3 rotates at the calculated rotational speed. The drum rotation control signal is output to the signal and drum rotation force applying device 26. The tire support rotation device 22 and the drum rotation force applying device 26 are configured such that the tire rotation force and the drum rotation force are controlled by the tire rotation control signal and the drum rotation control signal from the tire testing machine control unit 55, so that the drum 24 The measurement target tire 3 is rotated at the calculated rotational speed while maintaining the traveling speed at the set traveling speed (V). Accordingly, the tire testing machine 2 can rotate the measurement target tire 3 at the set travel speed (V) and the set slip rate (S). That is, the tire testing machine 2 can rotate the measurement target tire 3 with respect to the drum 24 in a state where the driving force is continuously applied.

  Therefore, in the measurement target tire 3, friction with the drum 24 increases, the tread portion 3a generates heat, and heat is stored. In addition, since the measurement target tire 3 is in a state in which a driving force is continuously applied by the tire testing machine 2, a tensile force F continuously acts on the tread portion 3a in any one of the tire circumferential directions. To do. That is, a shearing force is continuously generated in the tread splice portion 3b in the tire circumferential direction. For example, when the set slip ratio S = + 15 (%) and the set travel speed V of the measurement target tire 3 is 100 (km / h), the tire testing machine control unit 55 sets the above-described slip ratio (S). Since 15 = (Vt−100) / Vt × 100 from the mathematical formula, the measurement target tire 3 is rotated at the traveling speed (Vt) = 115 (km / h).

  Next, the tire testing machine 2 starts a test (step ST5). Here, when the measurement target tire 3 rotates at the set travel speed (V) and the slip rate (S), it is determined that the tire test is started. At this time, the test elapsed time counter unit 58 starts to count the test time. Accordingly, the test time (t) is counted by the test elapsed time counter unit 58 until the test of the tire testing machine 2 is completed.

Next, the temperature change detection unit 57 of the control device 5 acquires surface temperature distribution data (TD _n ), which is the surface temperature distribution of the tread portion 3a output to the control device 5 (step ST6). Here, the surface temperature distribution data (TD _n ) is temperature data (T1 _{n to} Tm _n ) measured at each sampling point (1 to _m ) by the nth sampling by the surface temperature measuring device 4.

Next, the temperature change detector 57 obtains the current surface temperature distribution data (TD _n ) and the surface temperature distribution data (TD _n-1 ) immediately before obtaining the current surface temperature distribution data (TD _n ). It is determined whether the difference (TD _n -TD _n-1 ) is equal to or less than the specified temperature change (−ΔT) (step ST7). That is, the temperature change detection unit 57 determines whether or not the relationship of (TD _n −TD _n−1 ) ≦ −ΔT is satisfied. Since a shearing force is continuously generated in the tread splice portion 3b, the one end portion 33a and the other end portion 33b are peeled off with the passage of time. Here, since the surface temperature of the tread portion 3a changes locally before and after the tread splice portion 3b peels off, the temperature change detection unit 57 detects a local temperature change of the surface temperature. Determine whether or not. Specifically, the temperature change detection unit 57 at all sampling points (1 to m), the current temperature at each sampling point (T1 _{n to} Tm _n ) and the temperature at each previous sampling point (1 to _m ). It is determined whether or not the difference from (T1 _{n-1 to} Tm _n-1 ) is not more than a specified temperature change (−ΔT).

Next, the tire testing machine control unit 55 acquires the current surface temperature distribution data (TD _n ) acquired by the temperature change detection unit 57 and the surface temperature distribution immediately before acquiring the current surface temperature distribution data (TD _n ). When it is determined that the difference (TD _n −TD _n−1 ) from the data (TD _n−1 ) is equal to or less than the specified temperature change (−ΔT) (Yes in step ST7), the test is terminated (step ST8). Here, the tire testing machine control unit 55 determines that the temperature change detection unit 57 has detected a temperature change in the surface temperature of the tread portion 3a due to the surface temperature of the tread portion 3a being lowered due to the separation of the tread splice portion 3b. Then, the rotation of the measurement target tire 3 by the tire testing machine 2 is stopped. Specifically, the tire testing machine control unit 55 outputs the operation stop command to the tire support rotation device 22 and the drum rotation force applying device 26 to stop the generation of the tire rotation force and the drum rotation force and perform the measurement. The target tire 3 is rotated. Here, when the measurement target tire 3 rotates at the set travel speed (V) and the slip rate (S), it is determined that the tire test is started. At this time, the test elapsed time counter unit 58 stops the time count of the test time. As a result, the test elapsed time counter unit 58 stops counting the test time (t).

  As described above, in the tire testing apparatus 1 and the tire testing method according to the embodiment, the driving force is continuously applied to the measurement target tire 3 by rotating the measurement target tire 3 with the slip ratio (S) by the tire testing machine 2. Is granted. As a result, the tire testing machine 2 can detect the occurrence of peeling of the tread splice portion 3b before the measurement target tire 3 bursts. Therefore, the tire testing apparatus 1 can accurately bond the tread splice portion 3b. Sexuality can be evaluated.

Next, the slip ratio control unit 56 acquires the current surface temperature distribution data (TD _n ) acquired by the temperature change detection unit 57 and the surface temperature distribution data immediately before acquiring the current surface temperature distribution data (TD _n ). the difference between _{(TD n-1) (TD} n -TD n-1) is determined to be less than the predetermined temperature change (-.DELTA.T) (step ST7 negative), test time (t) is increased initial slip ratio It is determined whether or not time (tx) has been exceeded (step ST9). Here, when the slip rate control unit 56 determines that the temperature change of the surface temperature of the tread portion 3a cannot be detected, the test time (t) by the test elapsed time counter unit 58 increases the slip rate (S) stepwise. It is determined whether or not the initial slip rate increase time (tx), which is a time, has been exceeded. In the embodiment, the initial slip ratio increase time (tx) is set when the initial value is input (step ST1). However, the present invention is not limited to this, and for example, the initial slip ratio increases during the test. Time (tx) may be set. If the slip rate control unit 56 determines that the test time (t) is equal to or shorter than the initial slip rate increase time (tx) (No in step ST9), the test time (t) sets the initial slip rate increase time (tx). Until it is determined that the temperature is exceeded, the temperature change detection unit 57 acquires the temperature distribution data again (step ST6), and repeats the determination of whether or not the temperature change of the surface temperature of the tread portion 3a has been detected (step ST7).

  Next, when the slip rate control unit 56 determines that the test time (t) exceeds the initial slip rate increase time (tx) (Yes in Step 9), the slip rate control unit 56 increases the slip rate (S) (Step ST10). That is, the slip ratio control unit 56 adds the slip ratio increase amount (ΔS) to the set slip ratio (S) to obtain the slip ratio (S) (S = S + ΔS). Therefore, the tire testing machine 2 rotates the measurement target tire 3 with the increased slip ratio (S). Note that the number of increases in the slip ratio is not limited.

  Next, the control device 5 increases the slip rate increase time (tx) (step ST11). That is, the control device 5 adds the slip rate increase time (Δtx) to the initial slip rate increase time (tx) to obtain the slip rate increase time (tx) (tx = tx + Δtx). Accordingly, when the slip rate control unit 56 determines that the test time (t) exceeds the increased slip rate increase time (tx) in step ST9 (Yes in step 9ST), the slip rate (S) is further increased (step ST10). ). That is, the slip ratio (S) of the rotating measurement target tire 3 is increased stepwise with the test time (t). Thereby, based on the limit value of the set slip ratio (S), the measurement target tire 3 can be compared, such as a comparison with a reference slip ratio or a comparison between various measurement target tires 3. The adhesiveness of the tread splice portion 3b can be evaluated with high accuracy. In addition, it can be evaluated that the measurement target tire 3 having a higher slip ratio (S) limit value has better adhesion of the tread splice portion 3b.

  Furthermore, since the operation of the tire testing machine 2 can be stopped at a stage before bursting, the degree of peeling of the tread splice portion 3b can be visually recognized before the measurement target tire 3 bursts. Thereby, the adhesiveness of the tread splice portion 3b can be evaluated with high accuracy.

  Next, another tire test method according to the embodiment will be described. FIG. 5 is a diagram illustrating another flow of the tire test method according to the embodiment. The difference between the flow of the tire test method shown in FIG. 5 and the flow of the tire test method shown in FIG. 4 is that the temperature change between the sampling points at the same time is not detected by detecting the temperature change over time at the same sampling point. This is the point where changes are detected. Since the other flow of the tire test method shown in FIG. 5 is the same as the flow of the tire test method shown in FIG. 4, the same parts will be omitted or simplified for explanation.

The temperature change detection unit 57, for example, among the temperatures (T1 _{n to} Tm _n ) of the sampling points (1 to _m ) of the acquired current surface temperature distribution data (TD _n ), the minimum temperature (TMIN _n ), It is determined whether or not the difference from the maximum temperature (TMAX _n ) is equal to or less than the specified temperature change (−ΔT) (step ST12). That is, the temperature change detection unit 57 determines whether or not the relationship of (TMIN _n −TMAX _n ) ≦ −ΔT is satisfied. When a shearing force is continuously generated in the tread splice portion 3b, the one end portion 33a and the other end portion 33b are peeled off. Accordingly, the surface temperature of the part of the tread part 3a from which the tread splice part 3b has been peeled is lower than the part of the tread part 3a from which the tread splice part 3b has not been peeled off. Note that the target of determining whether or not the temperature is less than the specified temperature change (−ΔT) may be, for example, a temperature difference between adjacent sampling points.

The tire testing machine control unit 55 determines that the difference between the minimum temperature (TMIN _n ) and the maximum temperature (TMAX _n ) in the acquired current surface temperature distribution data is equal to or less than a specified temperature change (−ΔT). If it is determined (Yes at step ST12), the test is terminated (step ST8).

The tire testing machine control unit 55 determines that the difference between the minimum temperature (TMIN _n ) and the maximum temperature (TMAX _n ) in the acquired current surface temperature distribution data is less than the specified temperature change (−ΔT). If it is determined (No in step ST12), it is determined whether or not the test time (t) exceeds the initial slip rate increase time (tx) (step ST9).

  Below, the measurement result by the tire test apparatus and tire test method concerning the said embodiment is demonstrated. Table 1 is a table showing the test results of the tire test according to the example. The purpose of the test was to perform a tire test on the four types of test target tires having different manufacturing methods as the measurement target tires by the tire test apparatus according to the present invention, and to measure the time from the start of the test to the end of the test. This evaluates the adhesion of the tread splice of the target tire. The tire size of each test target tire was 245 / 35R17, the wheel size was 17 × 9JJ, the set load was 2 (kN), the air pressure was 200 (kPa), the slip angle was 0 degree, and the camber angle was 0 degree. . Further, the tire test was performed with the set travel speed set to 100 (km / h) and the slip rate set to +15 (%).

  As is apparent from Table 1, the test object tire according to the production method 2 has the longest test time of 5 minutes and 20 seconds, and then the test object tire according to the production method 4 is 2 minutes and 43 seconds, and then the production method. The test object tire according to 1 was 2 minutes and 35 seconds. The shortest test time was the tire to be tested according to Production Method 3, and the test time was 1 minute 30 seconds. As described above, since the measurement target tire 3 having a long test time can be evaluated as having excellent adhesion of the tread splice part, among the test target tires manufactured by the four types of manufacturing methods, It can be evaluated that the test object tire according to the manufacturing method 2 has the best adhesion of the tread splice portion 3b. On the other hand, it can be evaluated that the test target tire according to the manufacturing method 3 has the poorest adhesion at the tread splice. That is, it is possible to evaluate the adhesiveness of the tread splice portion 3b by the manufacturing method of the test target tire based on the length of the test time.

  As described above, the tire testing apparatus and the tire testing method according to the present invention are suitable for accurately evaluating the adhesiveness of the tread splice portion.

It is a schematic structure figure showing the tire testing device concerning an embodiment. It is an enlarged view of the test object tire of the tire testing device concerning an embodiment. It is an enlarged view of the test object tire of the tire testing device concerning an embodiment. It is a figure which shows the flow of the tire test method concerning embodiment. It is a figure which shows the other flow of the tire test method concerning embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire testing apparatus 2 Tire testing machine 21 Tire shaft 22 Tire support rotation apparatus 23 Tire load addition apparatus 24 Drum 25 Drum rotation shaft 26 Drum rotational force application apparatus 3 Tire to be measured 3a Tread part 3b Tread splice part 31 Carcass layer 32 Belt layer 33 tread rubber 4 surface temperature detection device 5 control device 51 input / output port 52 storage unit 53 processing unit 54 load application unit 55 tire testing machine control unit 56 slip rate control unit 57 temperature change detection unit 58 test elapsed time counting unit 6 input / output Device 61 Input device 62 Output device

Claims (12)

A tire testing machine for rotating a measurement target tire with respect to a temporarily mounted road surface in a state where a driving force or a braking force is continuously applied;
Surface temperature measuring means for measuring the surface temperature of the tread portion of the rotating measurement target tire;
In the presently acquired surface temperature distribution of the tread portion, when there is a temperature portion lower than the surface temperature distribution of the tread portion acquired immediately before, a temperature change detection is detected as a temperature change of the surface temperature of the tread portion. Means,
Equipped with a,
By detecting the temperature change, it is determined that the splice portion of the tread portion has been peeled off .   The tire test apparatus according to claim 1, wherein the temperature change detection unit detects a local temperature change of the measured surface temperature.   3. The tire testing apparatus according to claim 1, wherein the tire testing machine stops the rotation of the measurement target tire when the temperature change is detected by the temperature change detection unit. The tire testing machine has a slip ratio control means for controlling a slip ratio of the measurement target tire with respect to the temporary road surface,
The tire test apparatus according to any one of claims 1 to 3, wherein the slip ratio is in a range of 10% to 30%.   The tire test apparatus according to claim 4, wherein the slip ratio control means increases the slip ratio stepwise. The tire testing machine further includes load adding means for applying a load to the measurement target tire with respect to the temporary road surface,
The load applying means controls the load of the tire to be measured within a range of 30% or less of the maximum allowable load of the tire to be measured and more than 0%. The tire test apparatus described in 1. A test elapsed time counter,
The tire test apparatus according to any one of claims 1 to 6, wherein the test elapsed time counter measures a test elapsed time from the start of the test until the temperature change is detected. A procedure for rotating the measurement target tire with respect to the temporary road surface in a state where the driving force or the braking force is continuously applied by the tire testing machine,
A procedure for measuring the surface temperature of the tread portion of the rotating measurement tire;
In the presently acquired surface temperature distribution of the tread part, when there is a part having a temperature lower than the surface temperature distribution of the tread part acquired immediately before, a procedure for detecting the temperature change of the surface temperature of the tread part ,
A procedure for determining that the splice part of the tread part has been separated by detecting the temperature change;
A tire test method comprising:   The tire test method according to claim 8, wherein the step of detecting the temperature change of the measured surface temperature detects a local temperature change of the measured surface temperature.   The tire testing method according to claim 8 or 9, further comprising a step of stopping rotation of the measurement target tire by the tire testing machine when the temperature change is detected.   The tire test method according to any one of claims 8 to 10, further comprising a step of gradually increasing a slip ratio of the measurement target tire with respect to the temporary road surface.   The tire test method according to any one of claims 8 to 11, further comprising a procedure of measuring a test elapsed time from the start of the test to the detection of a temperature change.

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